When the channel state between an evolved Node B (eNB) and a User Equipment (UE) is poor, a Relay Node (RN) is installed between them to provide a better radio channel to the UE. In addition, use of an RN at a cell area where a channel from an eNB is in poor state can provide a high-speed data channel and extend cell service coverage. RNs have been introduced to eliminate shadowing areas and are widely deployed in a wireless communication system.
Conventionally, relaying was confined to the function of a repeater that simply amplifies a signal and forwards the amplified signal. However, more intelligent relay schemes have recently been developed. Furthermore, relaying is a requisite technology to reduce eNB installation cost and backhaul maintenance cost, while extending service coverage and increasing data throughput in a future-generation mobile communication system. Along with the growth of relaying techniques, there exists a need to support an RN used in a conventional wireless communication system for a new wireless communication system.
In a 3rd Generation Partnership Project (3GPP) Long Term Evolution-Advanced (LTE-A) system, an RN should transmit a Hybrid Automatic Repeat reQuest (HARQ) feedback in response to data transmission from an eNB. However, resources for use in HARQ feedback transmission from an RN have not been specified so far. As a result, HARQ feedback transmissions from an RN and a UE may collide, thereby remarkably degrading communication performance.